This invention relates in general to pump and clutch assemblies and in particular to an improved structure for a hub adapted to support an electromagnetic clutch and a hydraulic pump thereon.
Hydraulic pumps are well known devices which are adapted to be mechanically driven so as to generate a flow of hydraulic fluid to a controlled device. For example, hydraulic pumps are frequently provided on refuse trucks for operating a hydraulically actuated ram. The hydraulic pump is mechanically connected to the engine of the vehicle so as to be driven thereby. In some applications, the hydraulic pump is constantly driven by the vehicle engine, and one or more control valves are provided for selectively operating the ram. While this structure is operable, it is rather inefficient because a significant amount of energy is consumed by the pump as it is constantly driven.
To address this, it is known to provide a clutch between the vehicle engine and the hydraulic pump such that the hydraulic pump is driven by the vehicle engine only when operation of the controlled device is desired. For example, electromagnetically actuated clutches have been provided for selectively connecting the vehicle engine to the hydraulic pump. Such an electromagnetic clutch typically includes a circular pulley or similar member which is connected by a belt or other means to the vehicle engine. Thus, the pulley is constantly rotatably driven by the vehicle engine. The electromagnetic clutch further includes an armature assembly which is selectively connected to the pulley for rotation therewith. The hydraulic pump has an input shaft which is connected to the armature assembly for rotation therewith. Thus, when the clutch is engaged, the hydraulic pump is driven to cause actuation of the controlled device. When the clutch is disengaged, the hydraulic pump is not driven, thereby preventing operation of the controlled device.
It is known to mount both the hydraulic pump and the electromagnetic clutch on a common support bracket or similar structure for convenience. However, known support brackets are deficient because the rotational axes of the armature assembly of the electromagnetic clutch and the input shaft of the hydraulic pump are not maintained precisely co-axial. As a result, premature wear on the bearings in both the electromagnetic clutch and the hydraulic pump can occur. Accordingly, it would be desirable to provide an improved structure for supporting an electromagnetic clutch and a hydraulic pump which maintains the two components precisely co-axial during operation.